Jump to User Code in Alternate Flash Bank
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3-25
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Jump to User Code in Alternate Flash Bank
The flash device for the BIOS is a 4MB part consisting of eight 512K
banks. The BIOS occupies bank 0 only.
From the boot screen in the BIOS setup, you can select an alternate 512K
flash bank to load and execute instead of booting from standard devices in
the boot menu. If you select one of the alternate banks (banks 1 - 7), the
BIOS looks for the five character signature “_MOT_” in the last five bytes
of the selected 512K bank. If found, the BIOS disables interrupts, timers,
and the watchdog. Then it reads the top 64K of the selected bank into
segment 0F000h and jumps to 0F000:FFF0h. If the signature is not found,
the BIOS proceeds normally and attempts to boot from standard floppy
and hard drive devices.
Note
When the bank switch and jump occurs, it happens very late in
POST after all hardware is initialized.
Solution Systems Technologies Inc.
720-565-5995 | info@solusys.com | www.solusys.com
Solution Systems Technologies Inc.
720-565-5995 | info@solusys.com | www.solusys.com
